Battery stress relief system

Abstract

A charge system for a vehicle includes a battery charge path, a current limiting element, and a capacitor. The current limiting element is arranged in series along the battery charge path, and in parallel relative to the capacitor. During an inrush event, the current limiting element is configured to initially restrict current flow between the battery and the load, increasing the rate and amount with which the capacitor is used to meet the current demands of the load. Thus, the current limiting element allows the battery to gradually increase its supply of current to the load in a manner that does not jeopardize its health. Once a steady state level of charging has been reached, the current limiting element is able to reduce its resistance to current flow, and the battery is able to safely take over as the primary source of current to the load.

What is claimed is: 
     
         1 . A charge system for a vehicle, the charge system comprising:
 a battery charge path having a first end for electrical connection to a battery and a second end for electrical connection to a load;   a current limiting element arranged in series along the battery charge path; and   a capacitor charge path having a first end comprising an input terminal for electrical connection to a capacitor and a second end that is electrically coupled to the battery charge path at a location between the current limiting element and the second end of the battery charge path;   wherein, during a first phase of operation, the current limiting element is configured to provide a first degree of resistance to current flow between the first end of the battery charge path and the second end of the battery charge path, and during a second phase of operation the current limiting element is configured to provide a second degree of resistance to current flow between the first end of the battery charge path and the second end of the battery charge path that is less than the first degree of resistance.   
     
     
         2 . The charge system of  claim 1 , wherein the change in resistance is effectuated without the application of an external control input signal to the current limiting element. 
     
     
         3 . The charge system of  claim 1 , wherein the current limiting element comprises a thermally sensitive element. 
     
     
         4 . The charge system of  claim 3 , wherein the current limiting element comprises a negative temperature coefficient thermistor. 
     
     
         5 . A battery fuse terminal for a vehicle, the battery fuse terminal comprising:
 a housing securable relative to a battery exterior;   a battery attachment element supported by the housing;   a current limiting element supported by the housing;   a first conductive element extending between, and electrically coupling, the battery attachment element to the current limiting element;   a first electrical connector configured to engage a power terminal of an external device;   a second conductive element extending between, and electrically coupling, the current limiting element and the first electrical connector; and   a second electrical connector configured to engage a terminal coupled to a capacitor, the second electrical connector being electrically coupled to the second conductive connector element such that the second electrical connector is arranged in parallel with the first electrical connector.   
     
     
         6 . The battery fuse terminal of  claim 5 , wherein, during a first phase of operation, the current limiting element is configured to provide a first degree of resistance to current flow between the terminal of the battery and the first electrical connector, and during a second phase of operation the current limiting element is configured to provide a second degree of resistance to current flow between the terminal of the battery and the first electrical connector. 
     
     
         7 . The battery fuse terminal of  claim 6 , wherein the change in resistance provided by the current limiting element is effectuated without the application of an external control input signal to the current limiting element. 
     
     
         8 . The battery fuse terminal of  claim 7 , wherein the current limiting element comprises a negative temperature coefficient resistor. 
     
     
         9 . The battery fuse terminal of  claim 5 , wherein the first conductive element and battery attachment element are connected via a fusible link. 
     
     
         10 . A method for charging a load, comprising:
 causing current from a battery to flow through a current limiting element to a load;   causing current to flow from a capacitor to the load, wherein the capacitor is located in parallel to the current limiting element;   wherein, during a first phase, the current limiting element is defined by a first resistance and during a second phase, the current limiting element is defined by a second resistance that is less than the first resistance.   
     
     
         11 . The method of  claim 10 , wherein the change in the resistance of the current limiting element is effectuated without the application of an external control input signal thereto. 
     
     
         12 . The method of  claim 10 , wherein the current limiting element comprises a thermally sensitive element. 
     
     
         13 . The method of  claim 10 , wherein current flow from the battery is used to charge the capacitor during the second phase. 
     
     
         14 . The method of  claim 10 , wherein an amount of current flow from the capacitor to the load is greater than an amount of current flow from the battery to the load during the first phase. 
     
     
         15 . The method of  claim 10 , wherein a rate of current flow to the load from the battery increases over time. 
     
     
         16 . The method of  claim 10 , wherein current flow between the battery and the load is substantially prevented by the current limiting element during the first phase. 
     
     
         17 . The method of  claim 16 , wherein current flow between the battery and the load is substantially unrestricted by the current limiting element during the second phase. 
     
     
         18 . The method of  claim 17 , wherein the current limiting element transitions from being defined by the first resistance to being defined by the second resistance responsive to a change in a core temperature of the current limiting element. 
     
     
         19 . The method of  claim 18 , wherein the change in resistance of the current limiting is responsive to a core temperature of the current limiting element exceeding a threshold temperature range. 
     
     
         20 . The method of  claim 19 , wherein the current limiting element comprises a negative temperature coefficient thermistor.